Flickering page tab strip when setting view pager current item

Question

I have an infinitely scrolling ViewPager. To accomplish this, I have 5 items (0,1,2,3,4). When at rest, I am always at tab 2. After onPageScrollStateChanged returns to SCROLL_STATE_IDLE, I update the data source to put the current item in position 2 and then I set the ViewPager's current item to 2, like so:

    @Override
    public void onPageScrollStateChanged(int state) {
        if (state == ViewPager.SCROLL_STATE_IDLE) {
            populateForecastFragmentsArray();
            mPager.setCurrentItem(CENTER_PAGE_INDEX, false);
        }
    }

This works great to get the infinite scrolling I'm looking for, however, the PagerTabStrip flickers every time setCurrentItem() is called.

Is there another way to set the current item without using setCurrentItem? Is there a better way to handle infinite scrolling?

I have determined that the flickering happens during setCurrentItem, not populateForecastFragmentsArray(), but just to be complete, here is the code from populateForecastFragmentsArray():

public void populateForecastFragmentsArray () {
    mForecastFragmentArrayList.clear();
    for (int i = 0; i < mPageAdapter.getCount(); i++) {
        ForecastFragment fragment = new ForecastFragment();
        int offset = i - CENTER_PAGE_INDEX;
        fragment.calendar = (Calendar)mDisplayedDate.clone();
        fragment.calendar.add(Calendar.DAY_OF_YEAR, offset);

        mForecastFragmentArrayList.add(fragment);
    }
}

score 0 · Answer 1 · edited May 23 '17 at 12:14

Got the same problem, in my case I had two almost identical classes, and this problem was only in one case, in another everything worked good as it is. Didn't find any clues about why this happens, but found a hack in comments here: http://thehayro.blogspot.ru/2013/09/infiniteviewpager-infinite-paging.html In short:

Implement subclass of ViewPager like shown here: Change ViewPager animation duration when sliding programmatically
Remember current scroll duration
Set scroll duration to 0
Set current item in your pager with animation
Restore initial scroll duration

Flickering page tab strip when setting view pager current item

1 Answers1